Drier



Jan. 11, 1949.u K. E. MccoNNAUGHAY l 2,458,617

DRIER Filed March 10, 1945 rae/VH1 Patented Jant 11, 1949 UNITED STATES PATENT OFFICE DRIER Kenneth E. McConnaughay, West Lafayette, Ind. Application March 10, 1943, Serial No. 478,609

(C1. 3ft- 216) 4 Claims.

It is the object of my invention to produce a drier, and more particularly a drier suitable for use in the drying of crushed stone or other similar material used as an aggregate in paving compositions. More specically, it is my object to produce a drier which can be simply and economically constructed, which for its capacity will be relatively light in weight, and which will dry aggregate quickly and with a relative low expenditure of power. A further object of my invention is to produce a machine which in addition to drying the material passed through it will also serve to disintegrate any agglomerated lumps in such material.

In carryingI out my invention, I feed the aggregate to be dried through the lower portion of a housing, the upper portion of which is heated and ventilated. Within the housing are one or more horizon-tally disposed shafts each of which carries a multiplicity of outwardly projecting arms. Means are provided for rotating such shafts at a high rate of speed, and the shafts are positioned so that as they rotate the arms will engage the aggregate in the lower portion of the housing and throw it upwardly through the heated atmosphere in the upper portion of the housing. Desirably the rate of shaft rotation is great enough so that the aggregate will be impelled with such a velocity that it will strike the walls of the housing with considerable force.

The accompanying drawing illustrates my invention, Fig. 1 being a side elevation and Fig. 2 a top plan of the complete drier, portions of the structure being broken away in each view in order to illustrate the construction more clearly.

The drier illustrated in the drawing comprises a frame l which supports a drying housing II and a feed hopper i 2. The bottoms of the housing I I and hopper l2 are formed by the upper stretch of a belt conveyor I3 which passes around rolls I4 located at opposite ends of the frame and which moves in such a direction that it will carry aggregate from the hopper I2 into the housing Il., A gate I5 vertically .adjustable toward and away from the upper stretch of the conveyor I3 serves to regulate the rate at which the aggregate is fed from the hopper into the housing. The means employed for adjusting the gate I5 may takeany desired form, that shown in the drawing comprising a transversely extending shaft VIt provided with an operating hand-wheel il and with pinions I8 which mesh with racks I9 vertically movable with the gate I5. f

One or more shafts ZI extend transversely of the housing in parallel relation above the upper stretch of the conveyor i3. As (shown, therek are three such shafts 2 l; but the number may vary as desired. Each shaft carries within the housing I I a plurality of axially extending rows of generally radial arms 22 of such a length that in the rotation of the shaft their outer ends will pass close to the upper stretch of the conveyor i3. Desiraloly, each of the arms 22 is forwardly concave in the direction of rotation so that each arm as it rotates will tend to elevate the loose particles of aggregate on the conveyor.

Where, as indicated in the drawing, a plurality of the shafts 22 are provided, the housing is desirabiy equipped with vertical partitions 24 located between adjacentshafts 2| in a position to clear the louter ends of the arms 22. The lower edge of each of such partitions is spaced upwardly from the conveyor i3 and carries a swinging gate 25 extending substantially completely across the housing and having a height such that its lower edge will just clear the conveyor I3. A similar gate 25a is provided in the end wall of the housing adjacent the discharge end of the conveyor.

Any co-nvenient means may be employed for heating the atmosphere in the upper portion of the housing II. Where the partitions 24 extend f upwardly well into the upper portion of the housing, it is desirable to provide a heating means, such as a gas or oil burner 28, in each of the compartments into which the interior of the housing il is divided by the partitions Z4. For the purpose of carrying away moisture vaporized by the burners 28, the housing I I is provided with a vent stack 30, and may also be equipped with a blower 3i, the vent stack and blower being located so as to provide a forced circulation of air through the housing. The partitions 24 terminate short of the top wall of the housing, to permit the free passage of air from the blower te the stack, and their upper ledges vare 'desirably bent, as indicated at 24', to extend upwardly and rearwardly relative to the direction of movement of the upper stretch of the conveyor i3.

The various shafts 2l and at least one of the rollers I l are driven from any suitabie source of power. As shown, the shafts 2l are interconnected hy chain drives 35 so that they will all rotate at the same speed, and the center shaft 2! is driven through a speed-increasing drive 36 from a shaft 3l connected to an engine or driving motor 38. A speed reducing power-transmission mechanism dll of any convenient type interconnects the sha-ft 3l with the roll Il! at the discharge end of the housing. The drives are so designed that the .tips of the arms 22 will move at a linear velocity many times that of the conveyor I3. The speed of the shafts 2| should be at least great enough to throw the material being dried into the heated atmosphere in the upper part of the housing and desirably great enough to cause the particles of such material to be impelled with considerable force against the housing walls and partitions. The shafts 2| may rotate in either direction, but as shown rotate so that the ends of the arms 22 at the lower most part of their path of travel, move in the same direction as the conveyor.

In operation, the burners 28 are ignited, the hopper is filled with aggregate to be dried, and the blower 3| and driving means 38 are started. As

the conveyor moves, aggregate is carried from the v hopper into the bottom of the housing Il. As this aggregate reaches the vicinity of the rst shaft 2|, the arms 22 pick it up and throw it upwardly again and ag-ain into the heated atmosphere created by the first burner 28. As more and more aggregate is fed into the first compartment of the housing, some of it begins to collect on the conveyor |3 beyond the range of the rotating arms 22 and to accumulate against the face of the swinging gate 25. Eventually, a-ggregate accumulating at this point will create sufficient pressure on the gate 25 to cause it to swingagainst the force of gravity, thus permitting such aggregate to be carried by the conveyor beneath the swinging gate 25 into the next compartment, where the arms 22 on the second shaft pick it up and throw it upwardly into the heated atmosphere. In similar manner, the aggregate progresses from compartment to compartment beneath each swinging gate 25 until it escapes from the last compartment f and is discharged. The partitions 24 and swinging gates 25 prevent any particles of aggregate from being thrown immediately completely through the casing without having been subjected to the action of the drying atmosphere, while the inclined portion 24' at the upper edge of each partition prevents the particles from being thrown into the next compartment over the top of the partition.

The machine described acts not only as a drier, but also serves to break up any agglomerated lumps in the material being treated; for the rapidly moving arms strike the material with considerable force. In addition, some crushing action may occur between the tips of the arms and the conveyor.

Since the heat is applied only to the upper portion of the housing, moving parts such as the conveyor and the shafts 2| may remain comparatively cool. In the heated upper portion of the casing, each aggregate particle is completely surrounded by a drying atmosphere, and is free from contact with other particles or with a supporting surface. The movement of each particle while in the upper portion of the housing increases the volume of heated air with which it is brought into intimate contact, and thus speeds the drying action.

The abrupt change of velocity to which the aggregate particles are subjected is a further aid in drying; for surface moisture tends to be thrown from the particles each time their velocity changes. Where air velocity through the casing is relatively high, a large proportion of the moisture freed from the aggregate in this manner may be carried off by the moving air in an unvaporized state.

When, as is preferable, the shafts 2| are rotated at a speed suflicient to cause the aggregate particles to impinge with considerable force against the partitions and side and top walls of the housing the resulting impacts aid in the breaking up of agglomerated lumps and in freeing the particles from surface moisture.

The design of the drier is extremely flexible, great freedom of choice being permitted in respect to the number and arrangement of burners and in respect to the number and arrangement of air-admission and air-outlet openings.

I claim as my invention:

1. A drier for crushed stone and the like, comprising a horizontally elongated housing having side walls and a top wall and provided at opposite ends with inlet and discharge openings for the material to be dried, a conveyor in the lower portion of said housing for conveying material from the inlet opening to the discharge opening, said housing being provided above said conveyor and near opposite ends with air inlet and air discharge openings, means for causing air to flow upwardly thrown material from passing directly through said housing above said conveyor from the air inlet opening to the air discharge opening, means for heating such air, a plurality of spaced rotatable shafts extending horizontally across said housing above and transversely of said conveyor, each of said shafts being provided with a plurality of axially extending rows of generally radial arms, said arms having a length such that their outer ends will pass close to said conveyor as the shaft rotates, and means for rotating said shaft at a speed such that said arms will throw material on said conveyor upwardly into the heated upper portion of the housing, and a rigid vertical partition extending transversely of said housing between adjacent shafts to divide the interior` of the housing into compartments, said partition being arranged to permit communication between said compartments adjacent the top wall of the housing and having its lower edge spaced above said conveyorI to provide an opening through which the material being dried can pass from one compartment to the other on the conveyor, said partition between its lower edges and a point adjacent the top wall of the housing being imperforate to intercept material thrown upwardly by the arms on the shaft in one compartment and thereby prevent such upwardly thrown material from passing directly into the adjacent compartment.

2. The invention set forth in claim l with the addition of a swinging gate hinged adjacent the lower edge of the partition and extending downwardly therefrom to a point adjacent the conveyor.

3. A drier for crushed stone and the like, comprising a horizontally elongated housing having side walls and a top wall and provided at opposite ends with inlet and discharge openings for the material to be dried, a 'conveyor in the lower portion of said housing for conveying material from the inlet opening to the discharge opening, said housing being provided above said conveyor and near opposite ends with air inlet and air discharge openings, means for causing air to ow through said housing above said conveyor from the air inlet opening to the air discharge opening, means for heating such air, a plurality of spaced rotatable shafts extending horizontally across said housing above and transversely of said conveyor, each of said shafts being provided with a plurality of axially extending rows of generally radial arms, said arms having a length such that their outer ends will pass close to said conveyor as the shaft rotates. and means for rotating said shaft at a speed such that said arms will throw material on said conveyor upwardly and cause it to impinge violently against the walls of the housing, and a rigid vertical partition extending transversely of said housing between adjacent shafts to divide the interior of the housing into compartments, said partition being arranged to permit communication between said compartments adjacent the top wall of the housing and having its lower edge spaced above said conveyor to provide an opening through which the material being dried can pass from one cornpartment to the other on the conveyor, said partition between its lower edge and a point adjacent the top wall of the housing being imperforate to intercept material thrown upwardly by thearms on the shaft in one compartment and therebs7 prevent such upwardly thrown material from passing directly into the adjacent compartment.

4. The invention as set forth in claim 3 with the addition of a swinging gate hinged adjacent the lower edge of the partition and extending downwardly therefrom to a point adjacent the conveyor.

KENNETH E. MCCONNAUGHAY.

REFERENCES CITED The following references are of record in the fue of this patent:

Number Number 6 UNITED STATES PATENTS Name Date Espinosa Mar. 11, 1890 Buttner et al Apr. 22, 1890 Proctor Apr. 19, 1-892 Sargent May 28, 1901 Ayres Mar. 12, 1907 Ruflin Aug. 9, 1910 Hopkins Sept. 3, 1912 Andrews July 20, 1915 Sargent Mar. 19, 1918 Rapp Dec. 31, 1918 Wadsworth July 3, 1923 Anderson May 1, 1928 Hiller Nov. 12, 1929 Kehoe July 15, 1930 Fulmer Jan. 6, 1931 Bartram May 29, 1934 Cottee Oct. 15, 1935 Peek Mar. 31, 1936 symons Mar. 8, 1938 Hickley, Jr May 28, 1940 Harrington Jan. 19, 1943 FOREIGN PATENTS Country Date Australia Jan. 25, 1906 Germany May 9, 1895 Germany Oct. 14, 1931 France June 24, 1930 Certificate of Correction Patent No. 2,458,617. January 11, 1949.

KENNETH E. MCCON N AUGHAY It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 21, claim 1, strike out the Words upwardly thrown material from passing direot1y; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent OHce.

Signed and sealed this 14th day of June, A. D. 1949.

[SEAL] THOMAS F. MURPHY,

Assistant Gommssz'oner of Patents. 

